The present invention relates in general to building panels having thermal insulating properties, and more particularly, to composite reinforced structural panels designed for use as rigid, load-bearing structural walls and ceilings for commercial buildings, residential homes and the like.
New construction costs have been spiraling upward over the years as a result of higher material and labor costs. Of particular interest has been the utilization of less costly materials and the prefabrication of new construction components to reduce labor costs. To this end, light-weight synthetic materials including foam synthetic resins and expanded synthetic foams, such as polyurethanes and polystyrenes have found their place in the construction industry by virtue of their having a number of properties that are highly desirable in building materials for various types of structures such as walls, roofs and the like. These properties include light-weight, exceedingly low thermal conductivity, resistance to abrasion, impermeability to moisture and acoustic insulation. However, such materials generally are deficient in structural strength and must therefore be combined in some manner with other materials having satisfactory structural properties.
For example, structural panels are known which include a thermal insulating core disposed within a wire mesh framework. A number of techniques have been utilized in the construction of these panels. Rockstead et al., U.S. Pat. No. 4,104,842 and Weismann, U.S. Pat. No. 3,305,991 disclose the filling of the interior of a prefabricated wire mesh framework with liquid foam components which harden to form the rigid insulating core. However, considerable difficulty has been experienced in maintaining the requisite components of the wire mesh framework in their appropriate orientation during fabrication and/or during application of the liquid foam components so that when the foam has solidified, an integral unit can be provided.
Chun, U.S. Pat. No. 4,253,288 initially assembles the wire mesh framework using a plurality of forms which are removed prior to filling the interior of the framework by blowing liquid insulating foam material into the framework. As one would appreciate, the necessity of using these forms and constraining devices to hold the framework components in their proper orientation during fabrication is undesirable.
Weismann, U.S. Pat. No. 3,879,908 avoids some of the aforementioned problems of the foam-in-place core by, instead, constructing the wire mesh framework and inserting a plurality of insulating core elements through passages that are provided within the framework. These insulating core elements must be dimensioned so as to be freely and easily passed between adjacent components of the framework which results in permeability of the resulting panel to moisture, as well as lacking an integral panel construction. To this end, there is applied a layer of a bonding agent to bond the insulating core elements to the components of the wire mesh framework and, to some degree, to provide a moisture barrier.
One solution to avoiding the separation inherent in the above panel construction technique is known from Chen, U.S. Pat. No. 4,611,450, Hibbard, U.S. Pat. No. 4,768,324 and Artzer, U.S. Pat. Nos. 4,297,820 and 4,226,067. This construction technique interdigitates the insulating core elements with the components of the wire mesh framework during the fabrication process. However, once again the incorporation of individual insulating core elements precludes the formation of an integral structural panel, as well as reducing its mechanical strength.
The fabrication of structural panels including an integral, rigid insulating core are known from Giurlani, U.S. Pat. No. 4,785,602 and Deinzer, U.S. Pat. No. 4,505,019. In Giurlani, a one-piece insulating core member is disposed between a pair of wire meshes having cross tie rod-like members pushed transversely through the insulating core member and secured to the wire mesh. In Deinzer, a similar structural panel is disclosed with the cross tie rod-like members being angularly disposed within the insulating core member.
Despite the advantages of the integral structural panels achieved by Giurlani and Deinzer, the use of cross tie rod-like members are undesirable. In this regard, each of the rod-like members are separate from one another and do not create a unified reinforcement of the structural panel, in addition to requiring additional labor costs associated with the insertion of each rod-like member. To this end, Deinzer also discloses the use of serpentine shaped rod-like reinforcing members arranged in spaced apart relationship within the wire mesh framework. However, in order to accommodate these serpentine shaped rod-like members, it is necessary that Deinzer form the insulating core from liquid synthetic material which is cast within the wire mesh framework about the serpentine shaped rod-like members.
For a number of reasons, it has been found desirable to incorporate serpentine shaped rod-like members into the wire mesh frameworks of structural panels having insulating cores. Although a number of structural panels are known which incorporate these serpentine shaped rod-like members, the techniques disclosed for fabricating the structural panels have a number of disadvantages. For example, Chun requires the prefabrication of the wire mesh framework using forms interdigitated between the serpentine shaped rod-like members during fabrication. Similarly, Chen, Rockstead et al., and Weismann also require the prefabrication of the wire mesh framework. Once fabricated, the insulating core is formed from a liquid synthetic material using molds and spray application. A similar molding process is disclosed in Deinzer as noted. In Artzer, the structural panel requires the use of strips of insulating core elements separately interdigitated between the serpentine shaped rod-like members.
In the fabrication of these structural panels, it is desirable to provide the insulating core as an integral, rigid one-piece member integrated with the serpentine shaped rod-like reinforcing members in that it provides greater structural integrity to the panel as well as maintaining the dimensions and space relationships of the components forming the wire mesh framework. There is heretofore unknown a fabrication technique for these structural panels which employ an integral, rigid one-piece insulating core and a plurality of interdigitated serpentine shaped rod-like members as noted hereinabove.